Rotor of an open end spinning device

ABSTRACT

A room or space is provided between the exterior room or space of the spinning device and the clearance gap for the rotor shaft so as to bypass the air flow around the rotor shaft bearings. This reduces the possibility of contamination of the bearings and lubrication leakage from the bearings. In another embodiment, the air flow path communicates the exterior room directly with the interior space of the housing while, in still another embodiment, the bearings are sealed into the same space as the interior of the housing.

United States Patent [1 1 Schiltknecht [4 11 Nov. 6, 1973 ROTOR OF AN OPEN END SPINNING DEVICE [75] Inventor: Adolf Schiltknecht,Winterthur,

Switzerland [73] Assignee: Ricter Machine Works, Ltd.,

Winterthur, Switzerland [22] Filed: June 15, 1971 [2]] Appl. No.: 153,240

[] Foreign Application Priority Data Primary Examiner-John Petrakes Attorney-Kenyon & Kenyon Reilly Carr & Chapin [57] ABSTRACT A room or space is provided between the exterior room or space of the spinning device and the clearance gap June 19, 1970 Switzerland 9317/ for the rotor Shaft so as to yp the air flow around the rotor shaft bearings. This reduces the possibility of 2% S Z 33 33- 3 contarnination of the bearings and lubrication leakage 2 i h l 57/58 129 from the bearings. In another embodiment, the air flow [5 1 F e 0 Scare 5 path communicates the exterior room directly with the 1. 1 interior space of the housing while, in still another embodiment, the bearings are sealed into the same space [56] UNITE S gFZ T QS SZqFENTS as the interior of the housing.

3,367,099 2/1968 Kubovy et al 57/58.89 5 Claims, 6 Drawing Figures Patentd Nov. 6, 1973 2 Sheets-Sheet l Fig. 7a

Fig.5 v

w RC Z N 5 m m BY (g Patented Nov. 6, 1973 2 Sheets-Sheet 2 m p. 0C N i R w m NT r ROTOR OF AN OPEN END SPINNING DEVICE This invention relates to an open end spinning device, and more particularly to a rotor supported in at least one bearing connected to the housing of an open end spinning device.

Heretofore, open end spinning machines have been known to have rotors which form fiber collecting surfaces. Generally, these rotors, with a tubular hub or with a shaft, have been rotatably supported in a closed stationary housing which is provided with means for supplying fibers into the rotor, and for taking off the yarn produced in the rotor. In these arrangements, the rotor has been rotated by a drive which is connected with a part of the hub or shaft protruding through a wall of the housing. A vacuum needed for spinning in the rotor has been generated by an external suction source e.g., in the case of the tubular hub, by means of a suction duct connected to the hub or, in the case of the rotor shaft being supported by bearings, by means of a suction duct connected to the housing. The vacuum in the rotor has also been generated by suitably shaping the rotor, e.g., by ventilating openings, with a corresponding pressure build up in the surrounding housing.

However, the known rotors, which are sometimes referred to as spinning chambers, often show the disadvantage when the bearings have been built directly into, or set onto, the housing that lubricants emerge.

from, the bearing'due to a pressure drop between the housing and the exterior room surrounding the housing. In one case, lubricants can be sucked into the housing from the bearing. This can result in contamination of the housing. Also, dust from the exterior not only cna be sucked into the bearing but also into the housing via the bearing. Thus, the housing is additionally contaminated. In the other case, lubricants can emerge from the bearing into the surrounding room. In both cases, a loss of lubricants in the bearing is caused which reduces the life of the hearing. In order to offset the lubricant losses, the lubricating cyclesmust be shortened and the housing must be cleaned more frequently which economically is undesirable.

The use of narrow clearances or of labyrinths in high speed spindle bearings in case of pressure differences between a bearing and an exterior room is also known. In such arrangements, however, the danger has arisen that the rotating parts are damaged at very high' rotational speeds with resultant power losses caused by the breaking action. Further, penetration of lubricants in the form of oil or fat mist and of dust cannot be avoided in these arrangements.

In the case of rotors of open end spinning devices, the conditions become most critical with high rotational speeds which in most cases exceed 15,000 r.p.m. Complete sealing of a spinning room of, e.g., the aforementioned housing in which the rotor is supported, proves difficult due to the protrusion and possible support of the rotating element in a wall of the housing because of the reasons mentioned above.

Accordingly, it is an object of the invention to avoid a permanent air throughput through the bearing of a rotor of an open end spinning device. It is another object of the invention thus to protect the bearing for a rotor of an open end spinning device from dust penetration into and'from lubricant losses from the bearing.

Briefly, the invention is directed to a rotor of an open end spinning device which has a fiber collecting surface disposed in an interior space of a housing at an interior pressure which differs from an exterior pressure while the device is in operation and which is rotatably supported in at least one bearing connected to the housing. The invention provides a space on the side of at least the bearing, arranged nearest to the interior of the housing, facing the housing which space is at a-pressure which is the same as in an end space adjacent to the bearing on the side distant from the housing. The term end space employed therein denotes the space in which the bearing terminates on the side distant from the housing. This space can be connected with the interior of the housing for exchanging air with the interior of the housing and is provided with an inflow crosssection area larger than the corss-section available for air throughput through the bearing or the bearing casing or housing, respectively, and corresponding to the sum of all air throughput openings in the corss-section area.

In one embodiment, the rotor can be connected by means of a hub to a shaft supported in the bearing or can be supported in the bearing by an annular extension directly. The bearing, which can be an antifriction, atplain or an air bearing, can be arranged directly in a wall of the housing or in a bearing casing or housing connected to the housing.

In another embodiment, the rotor can be rotatably supported in a bearing arranged outside the housing while an opening in the housing wall for a rotating part of the rotor, e. g., for the shaft, serves to connect the interior space fo the housing with an intermeidate space through which the interior space is connected to the exterior space so that air can be exhcnaged. This intermediate space can also be formed by a clearance between the housing and the bearing side facing the housing, which clearance together with the end space is kept at the pressure of the surrounding space by meansof an air connection of large throughflow cross-section area. The clearance can be provided by arranging the bearing or a bearing casing with a side facing the housing at such a distance that the throughflow opening in the housing wall can exchange air with the surrounding space and that the intermediate space and the end space are under the same pressure as the surrounding space. In a particular example, a by-pass duct is connected to the housing inside space and to the surrounding space. This by-pass duct has an air inflow crosssection area in the bearing or in the bearing casing and is arranged in the bearing casing connecting the bearing with the housing.

In still another embodiment, the bearing can also be arranged in a bearing casing or housing directly on the rotor housing. The bearing, casing or housing is then completely sealed off from the room surrounding the open end spinning device. Both the bearing side facing the housing as well as the bearing side distant from the housing, in this case, are connected only with the hous- I ing inside room, i.e., the intermediate room and the end junction with the accompanying drawings in which:

FIG. 1 illustrates a schematic cross-sectional view of an open end spinning device constructed according to the invention;

FIG. 1a illustratesa section of the open end spinning device along line Illl of FIG. 1;

FIG. 2 illustrates a cross-sectional view of another open end spinning device according to the invention;

FIG. 3 illustrates a cross-sectional view of still another open end spinning device according to the invention;

FIG. 4 illustrates a schematic cross-sectional view of an electrostatic open end spinning device according to the invention; and

FIG. 5 illustrates a schematic cross-sectional view of an alternative modified structure according to the invention.

Referring to FIG. 1, a rotor 1 of an open end spinning device is provided with an inside fiber collecting surface 2 and with an outside hub 3 which is connected to a shaft 4. The rotor l is mounted in a housing 5 with the shaft 4 passing through an opening 7 in a wall 6 of the housing 5 with a small clearance so that an air gap 8 is formed. The housing 5 is closed by a cover 9 and is provided with a connection nozzle 10 which connects with a vacuum source (not shown). Furthermore, the housing 5 is provided with a feed device (not shown), as is known, for feeding fibers into the spinning chamber and with a yarn take-off device (not shown), as is known, for the spun yarn. The shaft 4 is rotatably supported in bearings 11, 12 which are arranged in a bearing casing or housing 13 and is connected with a drive roll 14 arranged outside the bearing casing or housing 13 by means of which the rotor 1 can be rotated. The bearing casing or housing 13 is connected with the housing 5 by means of a support 15 with the upper face 16, as shown, being arranged at a distance A from the housing wall 6. The distance A is such that a larger air inflow cross-section area is formed between the housing wall 6 and the bearing casing or housing face 16 and, thus, the bearing 11 than in the opening available for an air throughflow in a cross-section 17 or 18 through the bearings 11 or 12. The sum of all openings available for an air throughflow in the cross-section 17 or 18 is represented by a cross-section area F as indicated in FIG. la. The bearings 11 and 12 and the air gap 8 are thus connected to an exterior space 19 wha,h can be the air space surrounding the open'end spinning device. I

During the spinning process a vacuum is created in the interior space 20 of the housing 5 as well as in the rotor l by the vacuum source acting on the nozzle 10. As a result, blind air from the exterior space 19 is sucked into the inside space 20 of the housing 5 via the air gap8. As the throughflow planes 17, 18 of the bearings ll, 12 are connected directly to the outside space 19, and as the air flow cross-sectional area of distance A is larger than the air flow cross-sectional area in the bearings 11, 12, the same pressure prevails within the bearings l1, 12 as in the outside space 19. Thus, no air flows through the bearings 11, 12 and no lubricant emerges to the outside.

Referring to FIG. 2, a rotor 21 of an open end spinning device provided with a fiber collecting surface 22 is mounted with a hub 23 on a shaft 24 and is arranged in a housing 25. The housing 25 is closed by a cover 26 and is provided with a connecting nozzle 27 which is connected with a vacuum source (not shown). In addition, the housing 25 is equipped in known manner with a supply device (not shown) for feeding fibers into the rotor 21 and with a take-off device (also not shown) for taking off a spun yarn. The shaft 24 is rotatably supported in bearings 28, 29 which again can be antifriction, plain, or air bearings and which are mounted in a bearing casing or housing 30. A spacer tube 31 is disposed between the bearings 28 and 29 in order to fix the axial position of the bearings 28 and 29. Outside the bearing casing or housing 30, the shaft 24 is connected to a drive roll 32 by means of which the shaft 24 and thus the rotor can be rotated. A circular cover 34 is provided on a face 33 of the bearing casing or housing 30 facing the rotor 21. This cover 34 includes a flat portion 35 which extends parallel to the face 33 and a depending cylindrical rim 36 which surrounds the hearing casing or housing 30. The portion 35 of the cover 34 also has an opening 37 through which the shaft 24 penetrates leaving a small clearance to form an air gap 38. The rim 36 is provided with a number of holes 39, only two of which are shown. The flat portion 35 of the cover 34 extends above the face 33 and together with the rim 36 encloses an intermediate space 40 which forms a larger air flow cross-section area than a crosssection area F (FIG. la) which corresponds to the air throughflow cross-section area available in the corsssection 41 or 41' of the bearings 28 or 29, respectively.

In order to avoid transmission of undesirable vibrations of the rotating rotor 21 to other parts of the open end spinning device, the bearing casing or housing 30 is arranged in a dampening sleeve 42 which, via a vibration dampening element 43, such as a rubber dampener, is connected elastically with a dampening sleeve 44 which extends into close vicinity to the holes 39 and is mounted in a collar or ring 45 of the housing 25. The inside diameter B of the dampening sleeve 44 is chosen with respect to the outside diameter C of the bearing casing or housing 30 so that an intermediate space 46 adjacent to the holes 39 is formed between the two. This space 46 also presents a larger airflow crosssection area than the air throughflow cross-section area available in the corss-section 41 or 41 respectively of the bearings 28 or 29 respectively. An opening 47 is provided in the ring 45 and in the dampening sleeve 44 in order to connect the intermediate space 46 with an exterior space 48. The dampening sleeve 44 is supported by the rim 36 of the cover 34 via an elastic seal 49 having an annular spring 50 so that the intermediate space 46 is connected with the interior space 51 of the housing 25 only via the air gap 38. A lubrication opening 52 is arranged in the bearing casing or housing 30 coaxially with the opening 47, to merge into a clearance 53 located between the spacer sleeve 31 and the bearing casing or housing 30 in order to provide for the introduction of lubricants to the bearings 28 and 29. The lubrication opening 52 is covered voer by a rubber ring 54 which is provided with an opening (not shown) through which lubricants can be, e.g., injected and which closes, preferably, under the influence of the I elasticity of the rubber.

As shown in FIG. 2, the interior space 51 of the housing 25 is connected directly with the exterior space 48 via the air gap 38 and the intermediate space 40 and no directly and exclusively via the air throughflow crosssection areas in the cross-sections 41, 41' in the bearings 28,29. Thus, the possibility of an air flow from the exterior space 48 to the interior space 51 through the bearings 29, 28 is practically eliminated. While the rotor 21 is in operation, i.e., while a vacuum prevails in the housing 25, air from the exterior space 48 is sucked into the interior space 51 through the air gap 38 from the intermediate space 40 and the intermediate space 46 (the air flow cross-section area of which is larger than the air throughflow cross-section areas in the bearings 28, 29). The air flows from the exterior space 48 along a longer path of larger cross-section area in the bypass duct consisting of the openings 47, the intermediate space 46, the holes 39 and the intermediate space 40 into the housing 25. The cross-section area in the cross-sections 41 and 41' is thus connected on both sides with the exterior space 48 so that the same pressure prevails at the outside and at the inside of the bearings 28, 29and so that no air can flow through the bearings 28, 29.

Referring to FIG. 3, a rotor 61 containing a fiber collecting surface 62 is connected by a hub 63 to a shaft 64 and is arranged in a housing 65 closed by a cover 66. The housing 65 is connected via a connencting nozzle 67 with a vacuum source (not shown) and is provided with devices (not shown) for supplying fibers to the fiber collecting surface 62 and for taking off a yarn pro duced from the rotor 61. The shaft 64 is rotatably supported in bearings 68, 69 which again can be antifriction, plain or air bearings arranged together with a spacer sleeve 70 in a bearing casing or housing 71. The bearing casing or housing 71 is pressed into a dampen ing sleeve 72 which extends past the lower face 73 of the bearing casing or housng 71 on the side distant from the rotor 61. In addition, a dampening sleeve 75 is connected with the dampening sleeve 72 via a vibration dampener 74 and is mounted ina depending collar or ring 76 of the housing 65 so that the bearings 68 and 69 are connected with the housing 65. The bearing 68 as above has, in a cross-section 77, a cross-section area connected directly to the inside space 78 of the housing 65 which area corresponds to the cross-section area F (FIG. Also, an air connection exists between the interior space 78 of the housing 65 and the bearing 69 as the bearing casing or housing 71 is provided with at least one recess 79 in the outer circumferential surface which extends from the face 73 distant from the rotor parallel to the shaft 64 to merge into an annular gap 80 located between the dampening sleeve 75 and the bearing casing or housing 71. The annular gap 80 extends along the length of the shaft 64 and merges into the inside space 78 of the housing 65. l

A cover 81 is also arranged in the dampening sleeve 72 to lie opposite and parallel to the face 73 of the bearing housing 71. This cover 81 is provided with an opening 82 through which the shaft 64'penetrates leaving a small clearance so that an air gap 83 is formed between the shaft 64 and the cover 81. A space 84 is thus defined between the face 73 and the cover 81 with a larger air flow cross-section area than the air gap 83 and than the air flow cross-section area in the crosssection 77 of the upper bearing 68 or in the crosssection85 in the lower bearing 69. Also, the recess 79 I duct 86, respectively, no noticeable air flow between the inside space 78 of the housing and an exterior space 87 outside the housing 65 via the bearings 68, 69 prevails.

In operation, if a vacuum prevails in the housing 65, the same vacuum acts on the bearings 68, 69. That is, as the air gap 83 provides a smaller air flow crosssection area than the by-pass duct 86, the same pressure prevails at the cross-section area in the crosssections 77, inside the bearings 68, 69 as in the housing 65. Further, since the air flow cross-section area of the by-pass duct 86 is larger than the one in the cross-sections 77, 85, the air sucked in through the air gap 83 from the exterior room 87 flows into the housing 65 via the by-pass duct 86 rather than via the bearings 69 and 68.

Referring to FIG. 4, an air bypass duct can also be used for the bearings 91, 92 of a twist insertion device 93 of anopen end spinning device 94 for electrostatic spinning. In this arrangement, the delivery rolls 95, 96 of a drafting arrangement (not shown) supply opened fiber material to a collector 94 of the twist insertion device 93. In addition, a suitable tension source 98 is provided for parallelizing and transporting the fibers to be spun between the delivery rolls and 96 and the twist insertion device 93. The delivery rolls 95 and 96 are connected to one pole of the tension source and the twist insertion device 93 is connected to the other pole. In order to avoid fly waste accumulations and poisoning-by ozone, if a tension is applied between the delivery rolls 95, 96 and thetwist insertion device 93, the delivery rolls 95 and 96 merge into a housing 99 which is connected with a vacuum source (not shown) via a connecting nozzle 100. The housing 99 is provided with an opening 102 in a wall opposite to the delivery rolls 95 and 96 through which the twist insertion device 93 penetrates leaving a clearance so that an air gap 103 is formed. The bearings 91, 92 are arranged in a bearing casing or housing 104 connected with the housing 99 by.a support 105. The bearing casing or housing 104 is arranged so that the upper face 106 of the upper bearing 91 is at a distance D from the wall 101 which is such that a larger air flow cross-section area is proviced between the face 106 and the wall 101 than the area F (FIG. 1a) corresponding to the air flow cross-section area in the cross-sections 107 and 108 in the bearings 91 and 92 respectively. In this way, no air flow between an inside room 109 of the housing 99 and an exterior room 110 is generated. The twist insertion device 93 is driven by a belt 111.

If a vacuum prevails in the'housing 99, air from the exterior room 110 is sucked through the air gap 103 into the housing 99. As the throughflow cross-sections 107 and 108 are subject to the pressure prevailing in the exterior space 110 on both sides, no air throughflow is generated through the individual bearings 91 V and 92.

Referring to FIG. 5, a rotor with a hub '122 also can be mounted on a shaft 123 and be arranged in a housing 124 onto which a bearing casing or housing 126 completely selaed off from an exterior space 125 is I mounted. The bearing casing 126 is secured to a wall 127 of the housing 124 and mounts a pair of bearings 128, 129, e.g., antrifriction, plain or air bearings therein for rotatably supporting the shaft 123. The shaft 123 extends through an opening 130 in the wall 127 out of the housing 124 and is connected with a drive.131 which is also arranged in the bearing casing or housing 126 for driving the shaft 123 and thus thr rotor 121. The housing 124 is closed by a cover 132 and is provided with a connecting nozzle 133 connected with a vacuum source (not shown) and devices (also not shown) for supplying fibers into the spinning chamber 121 and for taking off a yarn spun in the spinning chamber 121. No air connection or passage exists between the housing 124 and the exterior space 125 via the bearings 128 and 129 as the bearing casing 126 is completely sealed from the exterior room 125. If a vacuum prevails in the housing 124, the same pressure prevails in the bearings 128, 129 owing to the opening 130 and also in a space 134 of the bearing housing 126 surrounding the drive 131. Thus, no air flows through the bearings 128 and 129 and lubricants present in the bearings 128, 129 cannot be sucked into the housing 124 via the opening 130. It is noted that the air drawn from the interior of the housing 124 would enter from suitable openings in the cover 132.

It is also noted that a vacuum can also be generated in a rotor by the rotor itself. In this case, the rotor is provided with openings through which air flows into the surrounding housing due to the rotation of the rotor. Thus, a pressure higher than that inside the rotor and in a surrounding exterior space occurs in the housing, even if the housing is not equipped with a suction device. Further, the air by-pass ducts, for example, as shown in FIGS. 1 to 4, would function in the same manner as in the case of a vacuum in the housing; however, the air from the housing would not flow through the hearings to the exterior room but would flow through the by-pass ducts in the opposite direction.

The advantage of the inventive arrangement is that the bearing in which the rotor is rotatably supported is aerostatically relieved by means of an air by-pass duct in the'case of, e.g., air flowing into, or out of, the housing, so that the same pressure prevails on both sides of a bearing and lubricants present in the bearing cannot emerge from, and no dust can penetrate into, the bearmg.

What is claimed is:

I. In combination with an open end spinning device having a housing defining an interior space 51, a rotor having a fiber collecting surface disposed in said interior space at one end and a rotor shaft extending therefrom, and drive means 32 connected to said rotor shaft;

a bearing assembly removably supported on said housing for rotatably supporting said rotor shaft, said bearing assembly having a body member 30, 31, 42 having at least one antifriction bearing 28 fitted therein, said body member 30, 31, 42.

and said shaft defining together with said anti friction bearing an air-passage of predetermined cross-sectional area, said antifriction bearing having a first face directed towards said rotor and a second face directed towards said drive means 32,. said first face being adjacent a first space 40 communicating with said interior space 51 of the housing, said second face begin'in communication with a second space extending in the direction of said drive means; and a by-pass passage 46 communicating said first space 40 withan exterior space outside said spinning device, said by-pas s passage 46 having a larger crosssection 8 area than said air passage whereby virtually very to saud by-pass when said two faces of said antifriction bearing are subjected to different air pressures.

2. In combination with an open end spinning device having a housing defining an interior space 78, a rotor having a fiber collecting surface disposed in said interior space at one end and a rotor shaft extending therefrom, and drive means 32 connected to said rotor shaft;

a bearing assembly removably supported on said housing for rotatably supporting said rotor shaft, said bearing assembly having a body member 70, 71, 72 having at least one antifriction bearing 69 fitted therein, said body member 70, 71, 72 and said shaft defining together with said antifriction bearing an air-passage of predetermined cross-sectional area, said antifriction bearing 69 having a first face directed towards said rotor and a second face directed towards said drive means, said first face communicating with said interior space 78 of the housing, said second face being in communication with a space 84 within said body member 70,71, 72 extending in the direction of said drive means, and a by-pass passage 80 communicating with said interior space of said housing and said space 84 within said body member 70, 71, 72 said by-pass passage having a larger cross-section area than said air passage whereby virtually very little air flows through said air passage relative to said by-pass when said two faces of said antifriction bearing are subjected to different air pressures.

" i The combination as set forth in claim 1 which further includes a bearing casing secured to said housing and mounting said bearing therein, and a cover secured over one end of said casing to define said first space therebetween and spaced from said rotor to define an air gap therebetwcen to communicate said first space with said interior space, said cover having a plurality of openings therein communicating said first space with said exterior space via said by-pass passage.

I The combination asset forth in claim 1 which furthere includes a bearing casing mounting said bearing therein, and wherein said body member is a sleeve securing said casing to said housing, and a cover in said sleeve spaced from said bearing to define said first space therebetwcen, said cover being spaced from said rotor to define and annular gap connecting said first space with said exterior space. w The combination of an open end spinning device having a housing defining an interior space, a rotor having a fiber collecting surface disposed in said interior space; a bearing casing connected to said housing in communication with said interior space, said casing being sealed to the exterior thereof; a bearing in said casing rotatably supporting said rotor, means in said casing for rotating said rotor, and a nozzle communicating with said interior space for the withdrawal of air therethrough to evacuate said interior space whereby said interior spaceand said beaing are under equal pressure upon evacuation of said interior space.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,7 9,7 5 Dated November 6, 1973 Adolf Schiltknecht Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 33, "one" should be --can--. Column 2, line 1 "corss should be --cross--. Column 2, line 17, "corss' should be --cross--. Column 2, line 30, "f0" should be --of--. Column 2, line 30, :Lncermeidate" should be --intermediate--, Column 2, line 32, exhcnaged" should be --exchanged--. Column 2, line 5 "room" should be --space--. Column 2, line 58, "room" should be --space--. Column 2, line 59, "room" should be ---space Column 2, line 60, "room" should be --space--. Column 3, line #3, "wha,h" should be --which--. Column 4, line 23, "cores" should be "cross".

Column 1, line 39, 'corss" should be --cross--. Column line 53, "voer" should be ---over--. Column l, line 60, "no" should be --not--. Column 5, line 18, "connencting" should be --connecting--. Column 5, line 31, "ins" should be --in a--. a Column 6, line 13, "proviced" should be --provided--. Column 6, line 61, "selaed" should be --sealed--.

Column 7, line 2, "thr" should be --the--. Column 7, line 32, "room" should be --'space- Column 8, line after "very" insert little air flows through said air passage relative--. Column 8, line 2, "saud" should be --said--. Column 8, line 51, "and" should be --an--. Column 8, line 63, "beaing" should be --bearing--.

Signed and sealed this 16th day of April 197A.

(SEAL) Attest:

EDWARD MSLETCHERJR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM po'wso flo'ss) uscoMwnc 60376-P69 i U.S GOVERNMENT PRINTING OFFICE "ll O-Jll-JJJ, 

1. In combination with an open end spinning device having a housing defining an interior space (51), a rotor having a fiber collecting surface disposed in said interior space at one end and a rotor shaft extending therefrom, and drive means (32) connected to said rotor shaft; a bearing assembly removably supported on said housing for rotatably supporting said rotor shaft, said bearing assembly having a body member (30, 31, 42) having at least one antifriction bearing (28) fitted therein, said body member (30, 31, 42) and said shaft defining together with said antifriction bearing an air-passage of predetermined cross-sectional area, said antifriction bearing having a first face directed towards said rotor and a second face directed towards said drive means (32), said first face being adjacent a first space (40) communicating with said interior space (51) of the housing, said second face being in communication with a second space extending in the direction of said drive means; and a by-pass passage (46) communicating said first space (40) with an exterior space outside said spinning device, said by-pass passage (46) having a larger cross-section area than said air passage whereby virtually very little air flows through said air passage relative to said by-pass when said two faces of said antifriction bearing are subjected to different air pressures.
 2. In combination with an open end spinning device having a housing defining an interior space (78), a rotor having a fiber collecting surface disposed in said interior space at one end and a rotor shaft extending therefrom, and drive means (32) connected to said rotor shaft; a bearing assembly removably supported on said housing for rotatably supporting said rotor shaft, said bearing assembly having a body member (70, 71, 72) having at least one antifriction bearing (69) fitted therein, said body member (70, 71, 72) and said shaft defining together with said antifriction bearing an air-passage of predetermined cross-sectional area, said antifriction bearing (69) having a first face directed towards said rotor and a second face directed towards said drive means, said first face communicating with said interior space (78) of the housing, said second face being in communication with a space (84) within said body member (70, 71, 72) extending in the direction of said drive means, and a by-pass passage (80) communicating with said interior space of said housing and said space (84) within said body member (70, 71, 72) said by-pass passage having a larger cross-section area than said air passage whereby virtually very little air flows through said air passage relative to said by-pass when said two faces of said antifriction bearing are subjected to different air pressures.
 3. The combination as set forth in claim 1 which further includes a bearing casing secured to said housing and mounting said bearing therein, and a cover secured over one end of said casing to define said first space therebetween and spaced from said rotor to define an air gap therebetween to communicate said first space with said interior space, said cover having a plurality of openings therein comminicating said first space with said exterior space via said by-pass passage.
 4. The combination as set forth in claim 1 which further includes a bearing casing mounting said bearing therein, and wherein said body member is a sleeve securing said casing to said housing, and a cover in said sleeve spaced from said bearing to define said space therebetween, said cover being spaced from said rotor tO define an annular gap connecting said first space with said exterior space.
 5. The combination of an open end spinning device having a housing defining an interior space, a rotor having a fiber collecting surface disposed in said interior space; a bearing casing connected to said housing in communication with said interior space, said casing being sealed to the exterior thereof; a bearing in said casing rotatably supporting said rotor, means in said casing for rotating said rotor, and a nozzle communicating with said interior space for the withdrawal of air therethrough to evacuate said interior space whereby said interior space and said beaing are under equal pressure upon evacuation of said interior space. 